The next Coupe and Cabrio of the 3er are extremely signifcant for BMW in many ways , as is the next generation of 3er platform.
For example. The 3er segment - defined as Premium Entry is expected to grow this decade thanks to new emergring markets and customers downsizing to smaller more efficient premium cars.
The 3er platform is defined by the Sedan and Touring , Coupe and Cabrio and of course the X3.
With the new generation of modular structures designed to accomodate the 3er and 1er it is a particularly good investment for BMW. Because it makes both the 1er and 3er more profitable for the company. The modular platform begins with a central piece where front and rear sections are adapted (depending on the size of the concept) this allows BMW to seperate each model by relocating firewalls, suspension mounts etc to suit the character of each vehicle. This process will allow each the 1er and 3er to become more profitable between each unit.
The Platform can accomodate many "hats" or various body styles leading to each unit and body style to become more profitable than the previous E87/E90. Given that the 3er is in the Prime segment for growth that is why BMW are expanding and splitting the model line.
The new Coupe and Cabrio are defined by this , because the new car although it will remain within the current cars price range. It gets a stylish new appearance , again like the E92/E93 it will not be a Two door Sedan but again continue it's own identity , just like the E92/E93 which is BMW's successful 3er Coupe/Cabrio to date. originally the E92/E93 were to be called 4er that is why it is not simply, a two door sedan.
There is a mini-6er vibe to the new car which is signifcant because in Europe customers are specifying their 320d Coupes with the premium features normally found in high end luxury coupes.
The folding hard top remains due to the fact in key markets where a Blue sky is practically (at times) a permanent feature, outsells the relevant Coupe.
In China - The Cabrio outsells the Coupe especially between young females in China who like the Premium feel and security of a folding hard top.
The new Coupe and Cabrio continue there individual appearance with specific design treatment and individual appearance at the front and rear of the car, lower roof line and a more sporting character than the 3er sedan as you would expect the Coupe to be. Again the Coupe will be used as the basis for the M3 and as BMW M tell you and which other manufacturers fail to grasp is that to do an M car you must have a successful chassis , a perfect basis to start off with. And the 3er Coupe is a very good car to drive.
The testament to this is of course the M3. It is now four years since it's launch and we have heard the competition stress their car is the M3 killer but simply do not live up to this claim. Granted they are faster but an M3 is never about the straight-line , M3 updates are more about enhancing the driving experience which is why the Audi RS5 failed to conquer it and the Mercedes-Benz C63 Coupe failed to dethrone it. But you have to take note of the progress where it used to be miles behind the competition are getting closer yet.
The M3 is not your average faster 3er Coupe the engineering and development of the M3 takes on the aspects that need to distinguish an M car and something BMW M do very well it is all about bringing a new character with an Mcar and focusing on the individual aspects.
BMW M is the other sub-brand and you will see more scope for individuality.
The M3 will not die , because people will know it's an M3 just like the 1er M coupe is in fact an M1 to most (because it is based on the 1er). Even though it is marketed as 1er M Coupe. M3 and 4er can co-exist.